Researchers from the Indian Institution of Science (IISc) and University of Agricultural Sciences (UAS) published a new study that said that the increasing cases of vegetable salads causing food poisoning could be because of infectious bacteria that’s sneaking into the plant roots.
Recent years has seen numerous cases of salad contamination caused by E.coli and Salmonella bacteria. Although most salmonella outbreaks are linked to contamination post harvesting, these bacteria can enter a plant through contaminated soil.
But how does it enter the soil?
In the study, the researchers say unlike most bacteria that enter the root of the plant, Salmonellas sneak through a tiny gap created when a lateral root branches out from the plant’s primary root.
“This is the first time we have shown how different it is from other plant pathogens based on its ability to colonize the roots,” said Kapudeep Karmakar, a Ph.D. student in the Department of Microbiology and Cell Biology, IISc, and the first author of the paper published in BMC Plant Biology.
The research team said that when a lateral root pierces open the wall of primary root to spread across the soil, it leaves behind a tiny opening. They used fluorescent tagging and imaging, to figure out that Salmonella bacteria were using the gap to enter the plant. They also noticed that a plant with a greater number of lateral roots was more infected.
They found that if the salt concentration in soil increases, the plant produces more lateral roots.
In follow-up studies, the researchers plan to look at Salmonella infiltration in other edible vegetables and work on strategies to detect and prevent soil contamination.